Many of these writers used to study in writing clinics .

A．to investigate the security of Internet sites
B．to improve the security of the Internet system
C．to prevent hackers from breaking into websites
D．to download useful programs and information

A．those happy times appear still to be with us
B．there simply wasn"t any crime to worry about
C．many sites are not well-protected
D．hackers try out tricks on an Internet site without actually breaking in